1. Field
This disclosure relates generally to semiconductors, and more specifically, to semiconductors having a vacuum cavity.
2. Related Art
Micro-Electro-Mechanical Systems (MEMS) are implemented in a variety of products such as micro-gyroscopes and micro-accelerometers. Micro-gyroscopes require a sealed cavity or enclosure that is at a known atmospheric condition. Implementing a suitable package for very miniature devices with a sealed cavity is problematic, particularly when the chamber needs to be at vacuum. In one process a device wafer with edge standoffs formed of a sealant is placed on a heated chuck or platform. Once the device wafer is sufficiently heated, the chuck is moved toward a suspended cap wafer which also has standoffs formed of a sealant. When the standoffs of the two wafers contact, a cavity next to devices on the device wafer is formed. Radiation heat must be used from the heated chuck to sufficiently heat sealant of both the cap wafer and the device wafer. The required radiation heat can damage and modify the electrical properties of the device wafer which cause incorrect operation. The reliability of the sealing capability of two pressed sealing materials that are compressed when heated is an issue as the strength of the bond does not hold a vacuum long term.